The present invention relates to a speaker frame that supports a vibration system of a speaker and a speaker device having a speaker frame.
Most of speaker devices that are currently in practical use are electromotive speakers. This is because electromotive speakers can not only lower the low-tone reproducible limit frequency because they can produce large amplitudes but also realize considerably high efficiency depending on the design.
Electromotive speaker devices usually have a configuration that a magnetic circuit is fixed to a rear end wall of a speaker frame that supports a vibration system composed of a vibration plate, a voice coil bobbin, etc.
FIG. 1 is a rear view of a speaker frame of a conventional electromotive speaker device.
This speaker frame 101 is produced by integrating, by press-forming a steel plate, a rear end wall 102 to which a magnetic circuit is to be fixed, a damper support portion 104 which is formed at a position that is distant forward from the rear end wall 102 by a prescribed distance, an edge support portion 105 which is provided at a position that is distant forward from the damper support portion 104 by a prescribed distance, and plural frame arms 106 which connect the edge support portion 105 to the rear end wall 102 and the damper support portion 104.
The damper support portion 104 is a portion to which an outer circumferential flange of a damper is stuck and fixed. The damper supports a voice coil bobbin which is connected to the inner periphery of a vibration plate in such a manner that it can advance and retreat along the center axis of the speaker.
The edge support portion 105 is a portion to which an edge is stuck and fixed. The edge is connected to the outer periphery of the vibration plate.
Usually, four or five frame arms 106 are disposed so as to extend radially from the center axis of the speaker. In many cases, the width dimension w of each frame arm 106 is approximately constant from the edge support portion 105 side to the damper support portion 104 side and connecting portions between the outer periphery of the damper support portion 104 and the two side edges of each frame arm 106 assume circular arcs having a relatively small radius R1 (refer to JP-A-2000-244997, for example).
Each opening 107 formed by adjoining frame arms 106 assumes a fan shape because the width dimension w of the frame arms 106 is approximately constant.